EP1118793A2 - Hydraulic damping valve - Google Patents
Hydraulic damping valve Download PDFInfo
- Publication number
- EP1118793A2 EP1118793A2 EP01101094A EP01101094A EP1118793A2 EP 1118793 A2 EP1118793 A2 EP 1118793A2 EP 01101094 A EP01101094 A EP 01101094A EP 01101094 A EP01101094 A EP 01101094A EP 1118793 A2 EP1118793 A2 EP 1118793A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- valve
- sheet
- damping
- oil chamber
- piston
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 238000013016 damping Methods 0.000 title claims abstract description 167
- 239000000725 suspension Substances 0.000 claims abstract description 23
- 239000007789 gas Substances 0.000 description 6
- 230000002238 attenuated effect Effects 0.000 description 3
- 230000008602 contraction Effects 0.000 description 3
- 238000010030 laminating Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 239000012530 fluid Substances 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
- F16F9/32—Details
- F16F9/34—Special valve constructions; Shape or construction of throttling passages
- F16F9/348—Throttling passages in the form of annular discs or other plate-like elements which may or may not have a spring action, operating in opposite directions or singly, e.g. annular discs positioned on top of the valve or piston body
Definitions
- This invention relates to a damping valve for a hydraulic damping means, a hydraulic damping cylinder means with a damping valve, a pressure regulator with a damping valve and a suspension device for a four wheeled vehicle with damping valves.
- a hydraulic damper is used for example in vehicle suspension devices or systems and is constituted as follows: A piston rod is inserted in a cylinder. A piston serving as a valve seat member is attached to one end of the piston rod. The piston is freely slidably inserted in the cylinder to define oil chambers in the cylinder. The oil chambers are filled with working oil. As working oil flows between the oil chambers when the piston rod and the cylinder move in extending and contracting directions, damping forces are produced, which attenuate aftereffects of shocks from the road surface.
- the piston is provided with communication holes and an orifice that interconnect the oil chambers.
- the communication hole is opened and closed with a ring-shaped sheet valve.
- the sheet valve remains closed because the pressure of working oil in one oil chamber is low, and the working oil flows through the orifice formed in the piston into the other oil chamber.
- the working oil pressure increases and the working oil flows through the communication hole bored in the piston, push-opens the sheet valve, and enters the other oil chamber.
- the damping force characteristic of such a hydraulic damper as described above becomes as shown with the broken line in FIG. 5 a curve of secondary degree in a low speed range in which the working oil flows only through the orifice, and becomes a straight line in the medium to high speed range in which the sheet valve is push-opened.
- the hydraulic damper having the above-described damping characteristic for vehicles has a problem that the ride feeling of vehicle is impaired in the low speed range because of the low damping force.
- This damping valve structure provides a linear damping force characteristic in the low piston speed range as the working oil in one oil chamber SA (SB) flows through the communication hole 101a (101b) and the port 103a (102a) of the piston 101, and as the oil pressure opens the sub-valve 105 (104) and flows into the other oil chamber SB (SA).
- a damping valve for a hydraulic damping means with a valve seat member provided with at least one communication hole for a working oil flow and at least one sheet valve for opening and closing said communication hole, said sheet valve has a main valve sheet and at least one sub-valve sheet placed with one over the other with the sub-valve sheet located down-streams with regard to a working oil flow direction, wherein an oil chamber is provided between main valve sheet and a sub-valve sheet, and wherein at least one orifice is provided in said main valve sheet connecting the oil chamber with the communication hole.
- Such a damping valve is capable of providing appropriate damping force characteristics in a low piston speed range with a simple structure without inviting increase in the number of components and cost.
- a hydraulic damping cylinder means with a damping valve, a pressure regulator with a damping valve and a suspension device for a four wheeled vehicle with damping valves providing an appropriate damping force and being simple in structure.
- a hydraulic damping cylinder means comprising a piston inserted freely slidably in a cylinder, said piston divides said cylinder into an upper oil chamber and a lower oil chamber, wherein said piston is a valve seat member and is provided with at least one damping valve according to at least one of the claims 1 to 8, and said communication hole is provided for working oil flow from one of the upper and lower oil chamber to the other thereof.
- a pressure regulator comprising a piston inserted freely slidably in a cylinder, said piston divides said cylinder into an upper oil chamber and a lower oil chamber each connected with a hydraulic damping cylinder means, respectively, wherein said piston is a valve seat member and is provided with at least two damping valves according to at least one of the claims 1 to 8, and a communication hole of a first damping valve is provided for working oil flow from the lower oil chamber to the upper oil chamber and a communication hole of a second damping valve is provided for working oil flow from the upper oil chamber to the lower oil chamber.
- a Suspension device for a four wheeled vehicle with at least two hydraulic damping cylinder means comprising a piston inserted freely slidably in a cylinder, said piston divides said cylinder into an upper oil chamber and a lower oil chamber, and with a pressure regulator comprising a piston inserted freely slidably in a cylinder, said piston divides said cylinder into an upper oil chamber and a lower oil chamber each connected with one of the upper and lower oil chamber of the hydraulic damping cylinder means, respectively
- said piston of the hydraulic damping cylinder means is a valve seat member and is provided with at least one damping valve according to at least one of the claims 1 to 8, and said communication hole is provided for working oil flow from one of the upper and lower oil chamber to the other thereof, and/or wherein said piston of the pressure regulator is a valve seat member and is provided with at least two damping valves according to at least one of the claims 1 to 8, and a communication hole of a first damping valve is
- FIG. 1 shows an overall constitution in cross section of a vehicle suspension device or system comprising hydraulic dampers or damping valves.
- FIG. 2 is a partial, enlarged, detailed view of a piston portion of one hydraulic cylinder of the same suspension system.
- FIG. 3 is an enlarged, detailed view of the portion A of FIG. 2.
- FIG. 4 is an enlarged, detailed view of the piston portion of the same suspension system.
- the vehicle suspension device or system of this embodiment is for suspending for example right and left front wheels of a four-wheeled vehicle such as an automobile, and comprises as shown in FIG. 1 a pair of right and left hydraulic cylinders 1 (hydraulic damping cylinder means), and a pressure regulator 2 connected to those hydraulic cylinders 1.
- the hydraulic cylinders 1 and the pressure regulator 2 constitute a hydraulic damper means comprising damping valves.
- Each hydraulic cylinder 1 is constituted as follows: A piston rod 4 is inserted from above into a cylinder 3. A piston 5 is secured to the lower end portion of the piston rod 4 through a sleeve 6 by means of a nut 7 and inserted freely slidably into the cylinder 3. A connection member 9 is fitted into the lower end of the cylinder 3. A guide member 10 and a cap 11 are fitted to the upper end of the inside circumference of the cylinder 3. Oil-tight sealing between the cylinder 3 and the piston rod 4 is effected as an oil seal 12 held to the inside circumference of the guide member 10 comes in sliding contact with the outside circumference of the piston rod 4.
- the interior of the cylinder 3 is divided into an upper oil chamber S1 and a lower oil chamber S2, both filled with working oil.
- a plural number of communication holes 13 and 14 for interconnecting the oil chambers S1 and S2 are alternately bored at positions along a single circle in the piston 5.
- Ring-shaped sheet valves 15 and 16 for opening and closing the communication holes 13 and 14 are placed respectively over and under the piston 5.
- a small diameter orifice 17 for constantly interconnecting the communication holes 14 and the lower oil chamber S2 is formed in the upper part of the piston 5.
- Said piston 5 of the hydraulic damping cylinder means 1 serves as a valve seat member of an embodiment of a damping valve as described in detail below.
- Said embodiment of a damping valve with a piston 5 as a valve seat member comprises the sheet valve 15 being one type of valve and the sheet valve 16 being a further type of valve.
- Said one sheet valve 15 is built up by laminating four valves (valve sheets) 15a, 15b, 15c, and 15d of different diameters.
- the inside circumferential portions of the valves 15a, 15b, 15c, and 15d are sandwiched and secured between the piston 5 and the sleeve 6, with their outer circumferential portions are deflectable, and with the outer circumference of the largest diameter valve 15a is made to tightly contact the top surface of the piston 5 as shown.
- the other sheet valve 16 is constituted with a main valve (sheet) 16a and a sub-valve (sheet) 16b of different diameters, with their inner circumferential portions fixed and with the outer circumferential portions deflectable. That is to say, as shown in detail in FIG. 3, it is constituted by laminating both valves 16a and 16b, with the sub-valve 16b on the outer side (on the underside of the main valve 16a in the example of FIG. 3), with the inner circumferential portions of both valves 16a and 16b sandwiched among a washer 18, shims 19, 20, and the piston 5 and tightened with a nut 7.
- both valves 16a and 16b are deflectable, with the outer circumferential portion of the main valve 16a is in tight contact with the underside of the piston 5.
- the rigidity of the sub-valve 16b is set lower than that of the main valve 16a so that the former deflects more easily than the latter.
- the outside circumferential portion of the main valve 16a is provided with an initial deflection. Therefore, that portion is concave as seen from under and in contact with the underside of the piston 5. Since a shim 19 is interposed between the inside circumferential portions of the valves 16a and 16b, an oil chamber S is formed with the concave surface (underside) of the main valve 16a and the top surface of the sub-valve 16b, with the oil chamber S constantly in fluid communication with the communication holes 14 through the orifice 21 formed in the main valve 16a.
- the damping valve with the sheet valve 16 has been described as an embodiment wherein the valve seat member is identical with or at least part of the piston 5 which is movable within the cylinder 3.
- Said piston 5 has one sheet valve 16 having a specific damping characteristic (which will be described later) with regard to one flow direction of the working oil.
- a valve sheet 15 of a different type is provided.
- said piston 5 can be also provided with two sheet valves of the type of the sheet valve 16 described above, each for one of the flow directions.
- the damping characteristic can be adapted to be the same for both flow directions of the working oil.
- a desired damping characteristic can be individually adapted for each flow direction.
- the damping characteristic of the damping valve having a valve sheet of the type of the sheet valve 16 can be adjusted by changing the diameter of the orifice 21, the thickness of the shim 19 and the rigidity of the main valve sheet 16a and the sub-valve sheet 16b.
- the damping valve is shown in combination with the piston 5 as a valve seat member.
- a damping valve can be also provided within a hydraulic tube or the like with a fixed valve seat member in order to provide a specific damping characteristic of a working oil flowing to said tube or the like.
- the damping valve is shown with one sheet valve 16 associated to one communication hole 14.
- a damping valve can also be provided with a plurality of communication holes associated to one sheet valve as well as a plurality of such sheet valves respectively associated to communication holes provided within a single valve seat member.
- the damping valve described above teaches a sheet valve with one main valve sheet and one sub-valve sheet.
- a damping valve can also be provided with one main valve sheet in combination with one or more sub-valve sheets placed one over the other so that the sub-valve sheet is constituted by a plurality of valve sheet members without any space between said sheet members.
- the damping valve as mentioned above can be provided with a plurality of valve sheets placed one over the other wherein an oil chamber is provided between each of said valve sheets.
- each valve sheet being upstream serves as a main valve sheet with regard to the respective downstream valve sheet.
- at least one orifice is provided in said valve sheet which should be considered as a main valve sheet.
- the above-mentioned embodiment teaches a damping valve with one orifice provided in the main valve sheet.
- a damping valve can be also provided with a plurality of orifices or openings in the main valve sheet.
- the sub-valve sheet according to the embodiment mentioned above is not provided with an orifice.
- such a sub-valve sheet without an orifice constitutes a preferred embodiment and a further orifice can also be provided within said sub-valve sheet.
- Such a further orifice can be used instead of the orifice 17 as mentioned above or in addition thereto.
- the pressure regulator 2 comprises a cylinder 22 having a greater diameter portion 22a and a smaller diameter portion 22b, with a free piston 23 inserted freely slidably in the greater diameter portion 22a.
- the free piston 23 has an upward extending piston rod portion 23a with its top end provided with a piston 24 secured with a nut 25 and inserted freely slidably in the smaller diameter portion 22b.
- a plural number of communication holes 26 and 27 are bored alternately in positions approximately along a single circle in the piston 25. Ring-shaped sheet valves 28 and 29 for opening and closing the communication holes 26 and 27 are respectively placed over and under the piston 24.
- a cap 30 is fitted to the bottom end of the cylinder 22.
- the sheet valves 28 and 29 are constituted similarly to the sheet valve 16 provided at the piston 5 in the hydraulic cylinder 1. That is to say, one sheet valve 28 is constituted with a sub-valve (sheet) 28b placed over a main valve (sheet) 28a. The other sheet valve 29 is constituted with a main valve (sheet) 29a placed over a sub-valve (sheet) 29b. Oil chambers (not provided with symbols) formed in the respective sheet valves 28 and 29 are made to be always in fluid communication with the communication holes 26 and 27 through orifices 31 and 32 formed in the respective main valves 28a and 29a.
- the interior of the cylinder 22 is divided with the free piston 23 into an oil chamber S3 and a gas chamber S4, with the oil chamber S3 further divided into an upper oil chamber S31 and a lower oil chamber S32.
- the oil chambers S31 and S32 are filled with working oil
- the gas chamber S4 is filled with an inert gas.
- the upper oil chamber S31 is connected through a hydraulic hose 33 to the lower oil chamber S2 of the right hand side hydraulic cylinder 1
- the lower oil chamber S32 is connected through a hydraulic hose 34 to the lower oil chamber S2 of the left hand side hydraulic cylinder 1.
- the pressure regulator 2 is mounted on the vehicle body side, the cylinders 3 of the hydraulic dampers 1 are mounted on the wheel side through the connecting members 9, and the piston rods 4 are connected to the vehicle body side. Therefore, a pair of right and left front wheels of a four-wheeled vehicle are suspended from the vehicle body side by means of this suspension system.
- the damping valve with the sheet valves 28 and 29 has been described as an embodiment wherein the valve seat member is identical with or at least part of the piston 24 which is movable within the cylinder 22.
- Said piston 22 is provided with two sheet valves 28, 29 which are of the same type of the sheet valve 16 described above, each for one of the flow directions.
- the damping characteristic can be adapted to be the same for both flow directions of the working oil.
- the damping characteristic of the damping valve having valve sheet 28, 29 of the type of the sheet valve 16 can be adjusted by changing the diameter of the orifices 31, 32, the thickness of the shim and the rigidity of the respective main valve sheet 28a, 29a and the respective sub-valve sheet 28b, 29b.
- the damping valve is shown in combination with the piston 24 as a valve seat member.
- a damping valve can be also provided within a hydraulic tube or the like with a fixed valve seat member in order to provide a specific damping characteristic of a working oil flowing to said tube or the like.
- the damping valve is shown with one sheet valve 28 or 29 associated to one communication hole 26 or 27, respectively.
- a damping valve can also be provided with a plurality of communication holes associated to one sheet valve as well as a plurality of such sheet valves respectively associated to communication holes provided within a single valve seat member.
- the damping valve described above teaches a sheet valve with one main valve sheet and one sub-valve sheet.
- a damping valve can also be provided with one main valve sheet in combination with one or more sub-valve sheets placed one over the other so that the sub-valve sheet is constituted by a plurality of valve sheet members without any space between said sheet members.
- the damping valve as mentioned above can be provided with a plurality of valve sheets placed one over the other wherein an oil chamber is provided between each of said valve sheets.
- each valve sheet being upstream serves as a main valve sheet with regard to the respective downstream valve sheet.
- at least one orifice is provided in said valve sheet which should be considered as a main valve sheet.
- the above-mentioned embodiment teaches a damping valve with one orifice provided in the main valve sheet.
- a damping valve can be also provided with a plurality of orifices or openings in the main valve sheet.
- sub-valve sheet according to the embodiment mentioned above is not provided with an orifice.
- such a sub-valve sheet without an orifice constitutes a preferred embodiment and a further orifice can also be provided within said sub-valve sheet.
- each hydraulic damper 1 moves to extend or contract.
- the pistons 5 connected to the piston rods 4 move down in the cylinder 3.
- both of the main valve 16a and the sub-valve 16b of the sheet valve 16 are push-opened with the pressure in the upper oil chamber S1 and most of the working oil in the upper oil chamber S1 flows from the communication hole 14 in the piston 5 through the sheet valve 16 into the lower oil chamber S2.
- a damping force as indicated with the solid line (c) in FIG. 5 is produced with the flow resistance in the cylinder 1.
- the oil chamber S is formed by laminating the main valve 16a and the sub-valve 16b, and the oil chamber S is connected through the orifice 21 formed in the main valve 16a to the communication hole 14 of the piston 5, it is possible to constitute the sheet valve 16 with a minimum number of components, to simplify the constitution around the piston 5, and to reduce dimensions in the sliding direction.
- Another advantage of this embodiment is that the oil chamber S can be constituted simply without increasing the number of components because the initial deflection given to the main valve 16a is set so that the valve 16a does not to open unless the working oil pressure exceeds a certain value, and the convex surface of the main valve 16a set in this way is effectively used for defining the oil chamber S.
- Still another advantage is that, since the shim 19 is interposed between the main valve 16a and the sub-valve 16b of the sheet valve 16, the amount of the initial deflection given to the sub-valve 16b may be changed to any amount by adjusting the thickness of the shim 19. As a result, the damping force characteristic in the low speed range may be adjusted in a simple manner.
- this embodiment makes it possible to make the diameters of the main valve 16a and the sub-valve 16b of the sheet valve 16 as great as possible because the plural number of communication holes 13 and 14 are formed in positions approximately along a single circle in the piston 5, which in turn makes it possible to facilitate the adjustment of the damping force characteristics.
- the working oil flows from the lower oil chamber S32 to the upper oil chamber S31 through the sheet valve 28 and the communication hole 26 of the piston 24. Since the sheet valve 28 as describe above is similarly constituted to the sheet valve 16 in the hydraulic cylinder 1, a damping force indicated with a solid line (d) relative to the piston speed V in FIG. 6 is produced with the pressure regulator 2 as the working oil flows from the lower oil chamber S32 to the upper oil chamber to S31. Therefore, rolling of the vehicle body is restricted as extension and contraction of the right and left hydraulic cylinders 1 are restricted with the damping force produced with the pressure regulator 2.
- the working oil flows from the upper oil chamber S31 to the lower oil chamber S32 through the sheet valve 29 and the communication hole 27 of the piston 24.
- the sheet valve 29 as describe above is similarly constituted to the sheet valve 16 in the hydraulic cylinder 1
- a damping force indicated with a solid line (d') relative to the piston speed V in FIG. 6 is produced with the pressure regulator 2 as the working oil flows from the upper oil chamber to S31 to the lower oil chamber S32. Therefore, rolling of the vehicle body is restricted as extension and contraction of the right and left hydraulic cylinders 1 are restricted with the damping force produced with the pressure regulator 2.
- the pressure regulator 2 is also provided with the sheet valves 28 and 29 that are similar to the sheet valve 16 provided in each hydraulic cylinder 1, the same effect as obtained with each hydraulic cylinder 1 is also obtained with the pressure regulator 2.
- a vehicle suspension device or system in which a damping force is produced as working oil flows to push-open a ring-shaped sheet valve for opening and closing a communication hole formed through a valve seat member, with the sheet valve constituted with a main valve and a sub-valve, with their inside circumferential portions fixed and with their outside circumferential portions deflectable, with both of the valves placed one over the other with the sub-valve located on the outer side and with an oil chamber defined between both of them, and with the oil chamber connected to the communication hole in the valve seat member.
- a hydraulic damper or damping valve produces a damping force as working oil push-opens a ring-shaped sheet valve for opening and closing communication holes bored in a valve seat member, wherein the sheet valve is constituted with a main valve sheet and a sub-valve sheet, with their inside circumferential portions fixed and with their outside circumferential portions deflectable, the valve sheets are placed with one over the other with the sub-valve sheet located on the outer side and with an oil chamber formed between them, and with the oil chamber connected to the communication holes in the valve seat member.
- the damping valve portion may be constituted with a minimum number of components, with a simplified structure around the piston, and with a reduced dimensions in the sliding direction.
- the hydraulic damper according to the above embodiments is provided with an initial deflection given to the outside circumferential portion of the main valve sheet, the main valve sheet in the state of being bent back is secured to the valve seat member, and the oil chamber is formed with the concave surface of the main valve and the sub-valve.
- the oil chamber is formed in a simple manner without increasing the number of components.
- a shim is interposed between the main valve sheet and the sub-valve sheet, and the valves are secured to the valve seat member.
- the damping force characteristic in the low speed range may be easily adjusted.
- a plural number of communication holes are bored in positions approximately on a single circle in the valve seat member.
- the diameters of the main valve sheet and sub-valve sheet may be made as large as possible. This facilitates the adjustment of the damping force characteristics.
- the above mentioned embodiments are teaching a damping valve for a hydraulic damping means with a valve seat member 5,24 provided with at least one communication hole 14,26,27 for a working oil flow and at least one sheet valve 16,28,29 for opening and closing said communication hole 14,26,27.
- Said sheet valve 16,28,29 has a main valve sheet 16a,28a,29a and at least one sub-valve sheet 16b,28b,29b placed with one over the other with the sub-valve sheet 16b,28b,29b located down-streams with regard to a working oil flow direction.
- An oil chamber S is provided between main valve sheet 16a,28a,29a and a sub-valve sheet 16b,28b,29b, and at least one orifice 21,26,27 is provided in said main valve sheet 16a,28a,29a connecting the oil chamber S with the communication hole 14,26,27.
- the main valve sheet 16a,28a,29a and the sub-valve sheet 16b,28b,29b are ring-shaped, with their inside circumferential portions fixed to the valve seat member 5,24 and with their outside circumferential portions deflectable.
- the main valve sheet 16a,28a,29a and the sub-valve sheet 16b,28b,29b having different diameters.
- the outside circumferential portion the main valve sheet 16a,28a,29a is in tightened contact with the valve seat member 5,24 and the outside circumferential portion of the sub-valve sheet 16b,28b,29b is in tightened contact with the main valve sheet 16a,28a,29a.
- An initial deflection is given to the outside circumferential portion of the main valve sheet 16a,28a,29a, said main valve sheet 16a,28a,29a with the initial deflection is bent back in the working oil flow direction, and the oil chamber S is formed with a concave surface of the main valve sheet 16a,28a,29a and a facing surface of the sub-valve 16b,28b,29b.
- a rigidity of the sub-valve sheet 16b is set lower than that of the main valve sheet 16a.
- a shim 19 is interposed between the inside circumferential portions of the main valve sheet 16a,28a,29a and the sub-valve sheet 16b,28b,29b, and both of the valve sheets are secured to the valve seat member 5,24.
- a plurality of the communication holes 14,26,27 are bored in positions approximately on a single circle in the valve seat member 5,24.
- the hydraulic damping cylinder means comprises a piston 5 inserted freely slidably in a cylinder 3, said piston 5 divides said cylinder 3 into an upper oil chamber S1 and a lower oil chamber S2.
- Said piston 5 is a valve seat member and is provided with at least one damping valve as mentioned above, and the communication hole 14 of said damping valve is provided for working oil flow from one of the upper and lower oil chamber to the other thereof.
- the pressure regulator comprises a piston 24 inserted freely slidably in a cylinder 22.
- Said piston 24 divides said cylinder 22 into an upper oil chamber S31 and a lower oil chamber S32 each connected with a hydraulic damping cylinder means, respectively.
- Said piston 24 is a valve seat member and is provided with at least two damping valves as mentioned, and a communication hole 26 of a first damping valve is provided for working oil flow from the lower oil chamber S32 to the upper oil chamber S31 and a communication hole 27 of a second damping valve is provided for working oil flow from the upper oil chamber S31 to the lower oil chamber S32.
- Said piston 24 of the pressure regulator 2 serves as a valve seat member which is common for both damping valves so that the mentioned first and second damping valve with the common valve seat member (piston 24) constitute a single bi-directional damping valve.
- the suspension device for a four wheeled vehicle is provided with at least two hydraulic damping cylinder means 1 (as mentioned above) comprising a piston 5 inserted freely slidably in a cylinder 3.
- Said piston 5 divides said cylinder 3 into an upper oil chamber S1 and a lower oil chamber S2.
- Said suspension device is further provided with a pressure regulator 2 (as mentioned above) comprising a piston 24 inserted freely slidably in a cylinder 22.
- Said piston 24 divides said cylinder 22 into an upper oil chamber S31 and a lower oil chamber S32 each connected with one of the upper and lower oil chamber S1,S2 of the hydraulic damping cylinder means 1, respectively.
- Said piston 5 of the hydraulic damping cylinder means 1 is a valve seat member and is provided with at least one damping valve as mentioned above, and said communication hole 14 is provided for working oil flow from one of the upper and lower oil chamber to the other thereof, and/or said piston 24 of pressure regulator 2 is a valve seat member and is provided with at least two damping valves as mentioned above, and a communication hole 26 of a first damping valve is provided for working oil flow from the lower oil chamber S32 to the upper oil chamber S31 and a communication hole 27 of a second damping valve is provided for working oil flow from the upper oil chamber S31 to the lower oil chamber S32.
- Said piston 24 of the pressure regulator 2 within the vehicle suspension device serves as a valve seat member which is common for both damping valves so that the mentioned first and second damping valve with the common valve seat member (piston 24) constitute a single bi-directional damping valve.
Abstract
Description
- This invention relates to a damping valve for a hydraulic damping means, a hydraulic damping cylinder means with a damping valve, a pressure regulator with a damping valve and a suspension device for a four wheeled vehicle with damping valves.
- A hydraulic damper is used for example in vehicle suspension devices or systems and is constituted as follows: A piston rod is inserted in a cylinder. A piston serving as a valve seat member is attached to one end of the piston rod. The piston is freely slidably inserted in the cylinder to define oil chambers in the cylinder. The oil chambers are filled with working oil. As working oil flows between the oil chambers when the piston rod and the cylinder move in extending and contracting directions, damping forces are produced, which attenuate aftereffects of shocks from the road surface.
- Incidentally, the piston is provided with communication holes and an orifice that interconnect the oil chambers. The communication hole is opened and closed with a ring-shaped sheet valve.
- Here, in a low speed range when the speed of the piston in the hydraulic damper constituted as described above is low, the sheet valve remains closed because the pressure of working oil in one oil chamber is low, and the working oil flows through the orifice formed in the piston into the other oil chamber. When the piston speed reaches a medium or high value, the working oil pressure increases and the working oil flows through the communication hole bored in the piston, push-opens the sheet valve, and enters the other oil chamber.
- Therefore, the damping force characteristic of such a hydraulic damper as described above becomes as shown with the broken line in FIG. 5 a curve of secondary degree in a low speed range in which the working oil flows only through the orifice, and becomes a straight line in the medium to high speed range in which the sheet valve is push-opened.
- However, the hydraulic damper having the above-described damping characteristic for vehicles has a problem that the ride feeling of vehicle is impaired in the low speed range because of the low damping force.
- In view of the above, a damping valve structure has been proposed (Japanese laid-open patent application No. Hei-11-153173): As shown in FIG. 7,
disks Sub-valves close ports 102a and 103a bored through thedisks sub-valves - This damping valve structure provides a linear damping force characteristic in the low piston speed range as the working oil in one oil chamber SA (SB) flows through the communication hole 101a (101b) and the
port 103a (102a) of the piston 101, and as the oil pressure opens the sub-valve 105 (104) and flows into the other oil chamber SB (SA). - However, when the damping valve structure shown in FIG. 7 is used, the number of components increases because the
disks ports 102a and 103a are required. Moreover, since thesedisks disks - It is an objective of the present invention to provide a damping valve for a hydraulic damping means providing an appropriate damping force and being simple in structure.
- According to the present invention said objective is solved by a damping valve for a hydraulic damping means with a valve seat member provided with at least one communication hole for a working oil flow and at least one sheet valve for opening and closing said communication hole, said sheet valve has a main valve sheet and at least one sub-valve sheet placed with one over the other with the sub-valve sheet located down-streams with regard to a working oil flow direction, wherein an oil chamber is provided between main valve sheet and a sub-valve sheet, and wherein at least one orifice is provided in said main valve sheet connecting the oil chamber with the communication hole.
- Such a damping valve is capable of providing appropriate damping force characteristics in a low piston speed range with a simple structure without inviting increase in the number of components and cost.
- Preferred embodiments of the present invention are laid down in the dependent claims.
- Furthermore, it is also an objective of the present invention to provide a hydraulic damping cylinder means with a damping valve, a pressure regulator with a damping valve and a suspension device for a four wheeled vehicle with damping valves providing an appropriate damping force and being simple in structure.
- According to one further aspect of the present invention said objective is solved by a hydraulic damping cylinder means comprising a piston inserted freely slidably in a cylinder, said piston divides said cylinder into an upper oil chamber and a lower oil chamber, wherein said piston is a valve seat member and is provided with at least one damping valve according to at least one of the claims 1 to 8, and said communication hole is provided for working oil flow from one of the upper and lower oil chamber to the other thereof.
- According to one further aspect of the present invention said objective is solved by a pressure regulator comprising a piston inserted freely slidably in a cylinder, said piston divides said cylinder into an upper oil chamber and a lower oil chamber each connected with a hydraulic damping cylinder means, respectively, wherein said piston is a valve seat member and is provided with at least two damping valves according to at least one of the claims 1 to 8, and a communication hole of a first damping valve is provided for working oil flow from the lower oil chamber to the upper oil chamber and a communication hole of a second damping valve is provided for working oil flow from the upper oil chamber to the lower oil chamber.
- According to one further aspect of the present invention said objective is solved by a Suspension device for a four wheeled vehicle with at least two hydraulic damping cylinder means comprising a piston inserted freely slidably in a cylinder, said piston divides said cylinder into an upper oil chamber and a lower oil chamber, and with a pressure regulator comprising a piston inserted freely slidably in a cylinder, said piston divides said cylinder into an upper oil chamber and a lower oil chamber each connected with one of the upper and lower oil chamber of the hydraulic damping cylinder means, respectively, wherein said piston of the hydraulic damping cylinder means is a valve seat member and is provided with at least one damping valve according to at least one of the claims 1 to 8, and said communication hole is provided for working oil flow from one of the upper and lower oil chamber to the other thereof, and/or wherein said piston of the pressure regulator is a valve seat member and is provided with at least two damping valves according to at least one of the claims 1 to 8, and a communication hole of a first damping valve is provided for working oil flow from the lower oil chamber to the upper oil chamber and a communication hole of a second damping valve is provided for working oil flow from the upper oil chamber to the lower oil chamber.
- In the following, the present invention is explained in greater detail with respect to several embodiments thereof in conjunction with the accompanying drawings, wherein:
- FIG, 1 shows an overall constitution in cross section of a vehicle suspension device comprising hydraulic dampers or damping valves;
- FIG. 2 is a partial, enlarged, detailed view of a piston portion of one hydraulic cylinder of the same suspension system comprising hydraulic dampers or damping valves;
- FIG. 3 is an enlarged, detailed view of the portion A in FIG. 2;
- FIG. 4 is an enlarged, detailed view of the piston portion of a pressure regulator of the vehicle suspension device comprising hydraulic dampers or damping valves;
- FIG. 5 shows a damping force characteristic of a hydraulic cylinder of the vehicle suspension device;
- FIG. 6 shows a damping force characteristic of a pressure regulator of the vehicle suspension device; and
- FIG. 7 shows a damping valve structure in cross section of a conventional hydraulic damper.
-
- FIG. 1 shows an overall constitution in cross section of a vehicle suspension device or system comprising hydraulic dampers or damping valves. FIG. 2 is a partial, enlarged, detailed view of a piston portion of one hydraulic cylinder of the same suspension system. FIG. 3 is an enlarged, detailed view of the portion A of FIG. 2. FIG. 4 is an enlarged, detailed view of the piston portion of the same suspension system.
- The vehicle suspension device or system of this embodiment is for suspending for example right and left front wheels of a four-wheeled vehicle such as an automobile, and comprises as shown in FIG. 1 a pair of right and left hydraulic cylinders 1 (hydraulic damping cylinder means), and a
pressure regulator 2 connected to those hydraulic cylinders 1. The hydraulic cylinders 1 and thepressure regulator 2 constitute a hydraulic damper means comprising damping valves. - Here, the detailed constitution of the hydraulic cylinder 1 will be described in reference to FIGs. 1 to 3.
- Each hydraulic cylinder 1 is constituted as follows: A
piston rod 4 is inserted from above into acylinder 3. Apiston 5 is secured to the lower end portion of thepiston rod 4 through a sleeve 6 by means of anut 7 and inserted freely slidably into thecylinder 3. Aconnection member 9 is fitted into the lower end of thecylinder 3. Aguide member 10 and a cap 11 are fitted to the upper end of the inside circumference of thecylinder 3. Oil-tight sealing between thecylinder 3 and thepiston rod 4 is effected as anoil seal 12 held to the inside circumference of theguide member 10 comes in sliding contact with the outside circumference of thepiston rod 4. - The interior of the
cylinder 3 is divided into an upper oil chamber S1 and a lower oil chamber S2, both filled with working oil. As shown in FIG. 2 in detail, a plural number ofcommunication holes 13 and 14 for interconnecting the oil chambers S1 and S2 are alternately bored at positions along a single circle in thepiston 5. Ring-shaped sheet valves communication holes 13 and 14 are placed respectively over and under thepiston 5. As shown in FIGs. 2 and 3, asmall diameter orifice 17 for constantly interconnecting thecommunication holes 14 and the lower oil chamber S2 is formed in the upper part of thepiston 5. Saidpiston 5 of the hydraulic damping cylinder means 1 serves as a valve seat member of an embodiment of a damping valve as described in detail below. Said embodiment of a damping valve with apiston 5 as a valve seat member comprises thesheet valve 15 being one type of valve and thesheet valve 16 being a further type of valve. - Said one
sheet valve 15 is built up by laminating four valves (valve sheets) 15a, 15b, 15c, and 15d of different diameters. The inside circumferential portions of thevalves piston 5 and the sleeve 6, with their outer circumferential portions are deflectable, and with the outer circumference of thelargest diameter valve 15a is made to tightly contact the top surface of thepiston 5 as shown. - The
other sheet valve 16 is constituted with a main valve (sheet) 16a and a sub-valve (sheet) 16b of different diameters, with their inner circumferential portions fixed and with the outer circumferential portions deflectable. That is to say, as shown in detail in FIG. 3, it is constituted by laminating both valves 16a and 16b, with the sub-valve 16b on the outer side (on the underside of the main valve 16a in the example of FIG. 3), with the inner circumferential portions of both valves 16a and 16b sandwiched among awasher 18,shims 19, 20, and thepiston 5 and tightened with anut 7. The outer circumferential portions of both valves 16a and 16b are deflectable, with the outer circumferential portion of the main valve 16a is in tight contact with the underside of thepiston 5. Here, the rigidity of the sub-valve 16b is set lower than that of the main valve 16a so that the former deflects more easily than the latter. - The outside circumferential portion of the main valve 16a is provided with an initial deflection. Therefore, that portion is concave as seen from under and in contact with the underside of the
piston 5. Since ashim 19 is interposed between the inside circumferential portions of the valves 16a and 16b, an oil chamber S is formed with the concave surface (underside) of the main valve 16a and the top surface of the sub-valve 16b, with the oil chamber S constantly in fluid communication with thecommunication holes 14 through theorifice 21 formed in the main valve 16a. - Regarding the above hydraulic damping cylinder means, the damping valve with the
sheet valve 16 has been described as an embodiment wherein the valve seat member is identical with or at least part of thepiston 5 which is movable within thecylinder 3. Saidpiston 5 has onesheet valve 16 having a specific damping characteristic (which will be described later) with regard to one flow direction of the working oil. Regarding the opposite flow direction, avalve sheet 15 of a different type is provided. Thus, the damping characteristic will be different for the different flow directions. However, saidpiston 5 can be also provided with two sheet valves of the type of thesheet valve 16 described above, each for one of the flow directions. In this case, the damping characteristic can be adapted to be the same for both flow directions of the working oil. Moreover, with two sheet valves of the type of thesheet valve 16 described above a desired damping characteristic can be individually adapted for each flow direction. - Furthermore, the damping characteristic of the damping valve having a valve sheet of the type of the
sheet valve 16 can be adjusted by changing the diameter of theorifice 21, the thickness of theshim 19 and the rigidity of the main valve sheet 16a and the sub-valve sheet 16b. - Regarding the above described hydraulic damping cylinder means 1 the damping valve is shown in combination with the
piston 5 as a valve seat member. However, such a damping valve can be also provided within a hydraulic tube or the like with a fixed valve seat member in order to provide a specific damping characteristic of a working oil flowing to said tube or the like. - Within the above embodiments, the damping valve is shown with one
sheet valve 16 associated to onecommunication hole 14. However, such a damping valve can also be provided with a plurality of communication holes associated to one sheet valve as well as a plurality of such sheet valves respectively associated to communication holes provided within a single valve seat member. - Furthermore, the damping valve described above teaches a sheet valve with one main valve sheet and one sub-valve sheet. However, such a damping valve can also be provided with one main valve sheet in combination with one or more sub-valve sheets placed one over the other so that the sub-valve sheet is constituted by a plurality of valve sheet members without any space between said sheet members.
- Moreover, the damping valve as mentioned above can be provided with a plurality of valve sheets placed one over the other wherein an oil chamber is provided between each of said valve sheets. Thus, each valve sheet being upstream serves as a main valve sheet with regard to the respective downstream valve sheet. With regard thereto, at least one orifice is provided in said valve sheet which should be considered as a main valve sheet.
- Moreover, the above-mentioned embodiment teaches a damping valve with one orifice provided in the main valve sheet. Such a damping valve can be also provided with a plurality of orifices or openings in the main valve sheet.
- Moreover, the sub-valve sheet according to the embodiment mentioned above is not provided with an orifice. Also, such a sub-valve sheet without an orifice constitutes a preferred embodiment and a further orifice can also be provided within said sub-valve sheet. Such a further orifice can be used instead of the
orifice 17 as mentioned above or in addition thereto. - Next, details of the constitution of the
pressure regulator 2 will be described in reference to FIGs. 1 and 4. - As shown in FIG. 1, the
pressure regulator 2 comprises acylinder 22 having agreater diameter portion 22a and asmaller diameter portion 22b, with afree piston 23 inserted freely slidably in thegreater diameter portion 22a. Thefree piston 23 has an upward extendingpiston rod portion 23a with its top end provided with apiston 24 secured with anut 25 and inserted freely slidably in thesmaller diameter portion 22b. As shown in FIG. 4 in detail, a plural number of communication holes 26 and 27 are bored alternately in positions approximately along a single circle in thepiston 25. Ring-shapedsheet valves 28 and 29 for opening and closing the communication holes 26 and 27 are respectively placed over and under thepiston 24. Acap 30 is fitted to the bottom end of thecylinder 22. - The
sheet valves 28 and 29 are constituted similarly to thesheet valve 16 provided at thepiston 5 in the hydraulic cylinder 1. That is to say, one sheet valve 28 is constituted with a sub-valve (sheet) 28b placed over a main valve (sheet) 28a. Theother sheet valve 29 is constituted with a main valve (sheet) 29a placed over a sub-valve (sheet) 29b. Oil chambers (not provided with symbols) formed in therespective sheet valves 28 and 29 are made to be always in fluid communication with the communication holes 26 and 27 throughorifices - The interior of the
cylinder 22 is divided with thefree piston 23 into an oil chamber S3 and a gas chamber S4, with the oil chamber S3 further divided into an upper oil chamber S31 and a lower oil chamber S32. The oil chambers S31 and S32 are filled with working oil, and the gas chamber S4 is filled with an inert gas. As shown in FIG. 1, the upper oil chamber S31 is connected through ahydraulic hose 33 to the lower oil chamber S2 of the right hand side hydraulic cylinder 1, while the lower oil chamber S32 is connected through ahydraulic hose 34 to the lower oil chamber S2 of the left hand side hydraulic cylinder 1. - When the vehicle suspension system constituted as described above is employed, the
pressure regulator 2 is mounted on the vehicle body side, thecylinders 3 of the hydraulic dampers 1 are mounted on the wheel side through the connectingmembers 9, and thepiston rods 4 are connected to the vehicle body side. Therefore, a pair of right and left front wheels of a four-wheeled vehicle are suspended from the vehicle body side by means of this suspension system. - Regarding the above pressure regulator, the damping valve with the
sheet valves 28 and 29 has been described as an embodiment wherein the valve seat member is identical with or at least part of thepiston 24 which is movable within thecylinder 22. Saidpiston 22 is provided with twosheet valves 28, 29 which are of the same type of thesheet valve 16 described above, each for one of the flow directions. In this case, the damping characteristic can be adapted to be the same for both flow directions of the working oil. - As already explained, the damping characteristic of the damping valve having
valve sheet 28, 29 of the type of thesheet valve 16 can be adjusted by changing the diameter of theorifices sub-valve sheet 28b, 29b. - Regarding the above described
pressure regulator 2, the damping valve is shown in combination with thepiston 24 as a valve seat member. However, such a damping valve can be also provided within a hydraulic tube or the like with a fixed valve seat member in order to provide a specific damping characteristic of a working oil flowing to said tube or the like. - Within the above embodiments, the damping valve is shown with one
sheet valve 28 or 29 associated to onecommunication hole - Furthermore, the damping valve described above teaches a sheet valve with one main valve sheet and one sub-valve sheet. However, such a damping valve can also be provided with one main valve sheet in combination with one or more sub-valve sheets placed one over the other so that the sub-valve sheet is constituted by a plurality of valve sheet members without any space between said sheet members.
- Moreover, the damping valve as mentioned above can be provided with a plurality of valve sheets placed one over the other wherein an oil chamber is provided between each of said valve sheets. Thus, each valve sheet being upstream serves as a main valve sheet with regard to the respective downstream valve sheet. With regard thereto, at least one orifice is provided in said valve sheet which should be considered as a main valve sheet.
- Moreover, the above-mentioned embodiment teaches a damping valve with one orifice provided in the main valve sheet. Such a damping valve can be also provided with a plurality of orifices or openings in the main valve sheet.
- Moreover, the sub-valve sheet according to the embodiment mentioned above is not provided with an orifice. Also, such a sub-valve sheet without an orifice constitutes a preferred embodiment and a further orifice can also be provided within said sub-valve sheet.
- Next, the function of the vehicle suspension of this embodiment will be described.
- When a four-wheeled vehicle runs on a road and its right and left front wheels move up and down to follow road surface irregularities, the
cylinder 3 and thepiston rod 4 of each hydraulic damper 1 move to extend or contract. For example, when the right and left front wheels run over a bump on a road surface and thepiston rods 4 move down by the same travel relative to thecylinders 3 of the right and left hydraulic dampers 1, thepistons 5 connected to thepiston rods 4 move down in thecylinder 3. - When the
piston 5 moves up and down in thecylinder 3, working oil in the lower oil chamber S2 flows through the communication hole 13 formed in thepiston 5 to push-open thesheet valve 15, and into the upper oil chamber S1. At this time, flow resistance of working oil produces a damping force. The damping force (on the compression side) produced at this time is indicated with a solid line (a') relative to the piston speed (V) in FIG. 5. - At the same time, in the respective cylinders 1, working oil by the volume corresponding to part of the
piston rods 4 that enters thecylinders 3 flows from the lower chambers S2 through thehydraulic hoses free piston 23 and thepiston 24 move down as a single body in thecylinder 22 to compress the gas in the gas chamber S4. Since the cross-sectional areas of thegreater diameter portion 22a and thesmaller diameter portion 22b of thecylinder 22 of thepressure regulator 2 are set so that the volumes of the upper oil chamber S31 and the lower oil chamber S32 increase or decrease by the same amount, little working oil flows through thepiston 24 between the oil chambers S31 and S32. As a result, little damping force is produced with thepressure regulator 2. - Therefore, when the right and left front wheels move up to compress the right and left hydraulic cylinders 1 by the same amount, bouncing of the vehicle body after the wheel runs over an irregular road surface is attenuated with the damping force (Refer to the solid line a' in FIG. 5) produced as the working oil in each hydraulic cylinder 1 flows to push-open the
sheet valve 15. In this way, the ride feeling on the vehicle is improved. - In contrast to the above, when the right and left front wheels run over a recess on the road surface and the
piston rods 4 move up by the same travel relative to thecylinders 3, thepistons 5 connected to thepiston rods 4 move up in thecylinder 3. - When the
pistons 5 move up in thecylinders 3 as described above, pressure of the working oil in the upper oil chambers S1 increases. However, since the oil chamber S formed between the main valve 16a and the sub-valve 16b of thesheet valve 16 is connected to the upper oil chamber S1 through theorifice 21 formed in the main valve 16a and the communication holes 14 formed in thepiston 5, the pressure in the oil chamber S is the same as that in the upper oil chamber S1, and the pressure in the upper oil chamber S1 works on the top surfaces of the main valve 16a and the sub-valve 16b. - In a low speed range where the piston speed V is very small, or below V1 in FIG. 5, since the pressure in the upper oil chamber S1 is small, the
communication hole 14 remains closed with the main valve 16a and the sub-valve 16b of thesheet valve 16, the working oil in the upper oil chamber S1 flows through theorifice 17 bored through thepiston 5, and a damping force (on the extending side) is produced as shown with a solid line (a) in FIG. 5 with the hydraulic cylinder 1 by the flow resistance of the working oil. - After that, when the piston speed V increases and reaches V1, only the sub-valve 16b is push-opened with the pressure in the upper oil chamber S1, and the working oil in the upper oil chamber S1 flows through the
communication hole 14 and theorifice 17 in thepiston 5 and also through theorifice 21 of the main valve 16a, the oil chamber S, and the sub-valve 16b into the lower oil chamber S2 to produce a damping force with the flow resistance of the working oil as shown with a solid line (b) in FIG. 5. - When the piston speed V further increases to reach V2 in FIG. 5, both of the main valve 16a and the sub-valve 16b of the
sheet valve 16 are push-opened with the pressure in the upper oil chamber S1 and most of the working oil in the upper oil chamber S1 flows from thecommunication hole 14 in thepiston 5 through thesheet valve 16 into the lower oil chamber S2. At this time, a damping force as indicated with the solid line (c) in FIG. 5 is produced with the flow resistance in the cylinder 1. - As described above, when the piston speed V is in the very low range of V1 ≤ V ∠ V2, working oil exerts pressure from the
orifice 21 formed in the main valve 16a to the oil chamber S formed between the valves 16a and 16b, and flows as it push-opens only the sub-valve 16b. As a result, a damping force as shown with a solid line (c) in FIG. 5, that is appropriately higher than that produced with a conventional arrangement as shown with a broken line, is produced in the low speed range. In this case, since the oil chamber S is formed by laminating the main valve 16a and the sub-valve 16b, and the oil chamber S is connected through theorifice 21 formed in the main valve 16a to thecommunication hole 14 of thepiston 5, it is possible to constitute thesheet valve 16 with a minimum number of components, to simplify the constitution around thepiston 5, and to reduce dimensions in the sliding direction. - Another advantage of this embodiment is that the oil chamber S can be constituted simply without increasing the number of components because the initial deflection given to the main valve 16a is set so that the valve 16a does not to open unless the working oil pressure exceeds a certain value, and the convex surface of the main valve 16a set in this way is effectively used for defining the oil chamber S.
- Still another advantage is that, since the
shim 19 is interposed between the main valve 16a and the sub-valve 16b of thesheet valve 16, the amount of the initial deflection given to the sub-valve 16b may be changed to any amount by adjusting the thickness of theshim 19. As a result, the damping force characteristic in the low speed range may be adjusted in a simple manner. - Furthermore, this embodiment makes it possible to make the diameters of the main valve 16a and the sub-valve 16b of the
sheet valve 16 as great as possible because the plural number of communication holes 13 and 14 are formed in positions approximately along a single circle in thepiston 5, which in turn makes it possible to facilitate the adjustment of the damping force characteristics. - Incidentally, when the hydraulic cylinders 1 extend, an amount of working oil corresponding to part of the
piston rods 4 that come out of thecylinders 3 is supplied from the upper and lower oil chambers S31 and S32 of thepressure regulator 2 through thehydraulic hoses free piston 23 and thepiston 24 of thepressure regulator 2 as a single body move up in thecylinder 22, and the gas in the gas chamber S4 expands. However, since the cross-sectional areas of thegreater diameter portion 22a and thesmaller diameter portion 22b of thecylinder 22 of thepressure regulator 2 are set so that the volumes of the upper and lower oil chambers S31 and S32 change by the same amount, little working oil flows between the oil chambers S31 and S32 through thepiston 24, and therefore little damping force is produced with thepressure regulator 2. - Therefore, when the right and left hydraulic cylinders 1 extend by the same travel as the right and left front wheels move down by the same travel, the bouncing of the vehicle body after it has negotiated a road surface irregularity is attenuated with the damping forces (indicated with solid lines a, b, and c in FIG. 5) produced in respective hydraulic cylinders 1, and ride feeling is improved.
- On the other hand, in the case the hydraulic cylinder 1 on the right hand side contracts and the hydraulic cylinder 1 on the left hand side extends as the vehicle body makes a right turn for example, in a similar manner to that described above, a damping force indicated with a solid line (a') in FIG. 5 is produced with the left hand side hydraulic cylinder 1, and damping forces indicated with solid lines (a, b, and c) in FIG. 5 are produced with the right hand side hydraulic cylinder 1.
- When the right turn is made as described above, an amount of working oil corresponding to part of the
piston rod 4 entering thecylinder 3 of the left hand side hydraulic cylinder 1 flows from the lower oil chamber S2 through thehydraulic hose 34 into the lower oil chamber S32 of thepressure regulator 2. Also an amount of working oil corresponding to part of thepiston rod 4 coming out of thecylinder 3 of the right hand side hydraulic cylinder 1 flows from the upper oil chamber S31 of thepressure regulator 2 through thehydraulic hose 33 into the lower oil chamber S2 of the hydraulic cylinder 1. As a result, a working oil flow is produced in thepressure regulator 2 running from the lower oil chamber S32 to the upper oil chamber S31. That is, the working oil flows from the lower oil chamber S32 to the upper oil chamber S31 through the sheet valve 28 and thecommunication hole 26 of thepiston 24. Since the sheet valve 28 as describe above is similarly constituted to thesheet valve 16 in the hydraulic cylinder 1, a damping force indicated with a solid line (d) relative to the piston speed V in FIG. 6 is produced with thepressure regulator 2 as the working oil flows from the lower oil chamber S32 to the upper oil chamber to S31. Therefore, rolling of the vehicle body is restricted as extension and contraction of the right and left hydraulic cylinders 1 are restricted with the damping force produced with thepressure regulator 2. - When the vehicle makes an opposite, left turn in contrast to the above, and the left hand side hydraulic cylinder 1 extends and the right hand side hydraulic cylinder 1 contracts, damping forces indicated with solid lines (a, b, and c) in FIG. 5 are produced with the left hand side hydraulic cylinder 1 and a damping force shown with the solid line (a') is produced with the right hand side hydraulic cylinder 1.
- When the left turn is made as described above, an amount of working oil corresponding to part of the
piston rod 4 coming out of thecylinder 3 of the left hand side hydraulic cylinder 1 flows from the lower oil chamber S32 of thepressure regulator 2 through thehydraulic hose 34 into the lower oil chamber S2 of the left hand side hydraulic cylinder 1. Also an amount of working oil corresponding to part of thepiston rod 4 entering thecylinder 3 of the right hand side hydraulic cylinder 1 flows from the lower oil chamber S2 of the hydraulic cylinder 1 through thehydraulic hose 33 into the upper oil chamber S31 of thepressure regulator 2. As a result, a working oil flow is produced in thepressure regulator 2 running from the upper oil chamber S31 to the lower oil chamber S32. That is, the working oil flows from the upper oil chamber S31 to the lower oil chamber S32 through thesheet valve 29 and thecommunication hole 27 of thepiston 24. Since thesheet valve 29 as describe above is similarly constituted to thesheet valve 16 in the hydraulic cylinder 1, a damping force indicated with a solid line (d') relative to the piston speed V in FIG. 6 is produced with thepressure regulator 2 as the working oil flows from the upper oil chamber to S31 to the lower oil chamber S32. Therefore, rolling of the vehicle body is restricted as extension and contraction of the right and left hydraulic cylinders 1 are restricted with the damping force produced with thepressure regulator 2. - With the vehicle suspension system of this embodiment, in the case the right and left hydraulic cylinders 1 extend or contract in the same direction, shocks are absorbed and attenuated with the damping forces produced with the respective hydraulic cylinders 1.
In the case one of the right and left hydraulic cylinders 1 extends while the other contracts, rolling of the vehicle body is restricted as the extension and contraction of the hydraulic cylinders 1 are restricted with the damping force produced with thepressure regulator 2 in addition to the damping forces produced with the respective hydraulic cylinders 1. - Since the
pressure regulator 2 is also provided with thesheet valves 28 and 29 that are similar to thesheet valve 16 provided in each hydraulic cylinder 1, the same effect as obtained with each hydraulic cylinder 1 is also obtained with thepressure regulator 2. - As is clear from the above explanation, a vehicle suspension device or system in which a damping force is produced as working oil flows to push-open a ring-shaped sheet valve for opening and closing a communication hole formed through a valve seat member, with the sheet valve constituted with a main valve and a sub-valve, with their inside circumferential portions fixed and with their outside circumferential portions deflectable, with both of the valves placed one over the other with the sub-valve located on the outer side and with an oil chamber defined between both of them, and with the oil chamber connected to the communication hole in the valve seat member. As a result, appropriate damping force characteristics are provided with a simple constitution without increasing the number of components and cost.
- A hydraulic damper or damping valve according to the above embodiments produces a damping force as working oil push-opens a ring-shaped sheet valve for opening and closing communication holes bored in a valve seat member, wherein the sheet valve is constituted with a main valve sheet and a sub-valve sheet, with their inside circumferential portions fixed and with their outside circumferential portions deflectable, the valve sheets are placed with one over the other with the sub-valve sheet located on the outer side and with an oil chamber formed between them, and with the oil chamber connected to the communication holes in the valve seat member.
- Therefore, in the low speed range, the working oil flows through the orifice formed in the main valve sheet, exerts pressure in the oil chamber formed between both valve sheets, and push-opens the sub-valve sheet only, to provide a damping force characteristic appropriate in the low speed range. In this case, since it is constituted that the main valve sheet is placed over the sub-valve sheet to form an oil chamber between them, and the oil chamber is connected through the orifice formed in the main valve sheet to the communication holes of the valve seat member, the damping valve portion may be constituted with a minimum number of components, with a simplified structure around the piston, and with a reduced dimensions in the sliding direction.
- The hydraulic damper according to the above embodiments is provided with an initial deflection given to the outside circumferential portion of the main valve sheet, the main valve sheet in the state of being bent back is secured to the valve seat member, and the oil chamber is formed with the concave surface of the main valve and the sub-valve.
- Since an initial deflection given to the main valve sheet is set so that the main valve does not open unless the working oil pressure exceeds a certain value and since the concave surface of the main valve sheet formed by the setting is utilized to form the oil chamber, the oil chamber is formed in a simple manner without increasing the number of components.
- Regarding the embodiments a shim is interposed between the main valve sheet and the sub-valve sheet, and the valves are secured to the valve seat member.
- Since it is possible to optionally change the amount of initial deflection given to the sub-valve sheet by adjusting the thickness of the shim, the damping force characteristic in the low speed range may be easily adjusted.
- As can be taken from the embodiments a plural number of communication holes are bored in positions approximately on a single circle in the valve seat member.
- Since the plural number of communication holes are bored in positions approximately on the same circle in the valve seat member, the diameters of the main valve sheet and sub-valve sheet may be made as large as possible. This facilitates the adjustment of the damping force characteristics.
- The above mentioned embodiments are teaching a damping valve for a hydraulic damping means with a
valve seat member communication hole sheet valve communication hole sheet valve sub-valve sheet 16b,28b,29b placed with one over the other with thesub-valve sheet 16b,28b,29b located down-streams with regard to a working oil flow direction. An oil chamber S is provided between main valve sheet 16a,28a,29a and asub-valve sheet 16b,28b,29b, and at least oneorifice communication hole - The main valve sheet 16a,28a,29a and the
sub-valve sheet 16b,28b,29b are ring-shaped, with their inside circumferential portions fixed to thevalve seat member sub-valve sheet 16b,28b,29b having different diameters. - The outside circumferential portion the main valve sheet 16a,28a,29a is in tightened contact with the
valve seat member sub-valve sheet 16b,28b,29b is in tightened contact with the main valve sheet 16a,28a,29a. - An initial deflection is given to the outside circumferential portion of the main valve sheet 16a,28a,29a, said main valve sheet 16a,28a,29a with the initial deflection is bent back in the working oil flow direction, and the oil chamber S is formed with a concave surface of the main valve sheet 16a,28a,29a and a facing surface of the sub-valve 16b,28b,29b. A rigidity of the sub-valve sheet 16b is set lower than that of the main valve sheet 16a. A
shim 19 is interposed between the inside circumferential portions of the main valve sheet 16a,28a,29a and thesub-valve sheet 16b,28b,29b, and both of the valve sheets are secured to thevalve seat member - A plurality of the communication holes 14,26,27 are bored in positions approximately on a single circle in the
valve seat member - According to a embodiment, the hydraulic damping cylinder means comprises a
piston 5 inserted freely slidably in acylinder 3, saidpiston 5 divides saidcylinder 3 into an upper oil chamber S1 and a lower oil chamberS2. Said piston 5 is a valve seat member and is provided with at least one damping valve as mentioned above, and thecommunication hole 14 of said damping valve is provided for working oil flow from one of the upper and lower oil chamber to the other thereof. - According to a embodiment, the pressure regulator comprises a
piston 24 inserted freely slidably in acylinder 22. Saidpiston 24 divides saidcylinder 22 into an upper oil chamber S31 and a lower oil chamber S32 each connected with a hydraulic damping cylinder means, respectively. Saidpiston 24 is a valve seat member and is provided with at least two damping valves as mentioned, and acommunication hole 26 of a first damping valve is provided for working oil flow from the lower oil chamber S32 to the upper oil chamber S31 and acommunication hole 27 of a second damping valve is provided for working oil flow from the upper oil chamber S31 to the lower oil chamberS32. Said piston 24 of thepressure regulator 2 serves as a valve seat member which is common for both damping valves so that the mentioned first and second damping valve with the common valve seat member (piston 24) constitute a single bi-directional damping valve. - According to the embodiment, the suspension device for a four wheeled vehicle is provided with at least two hydraulic damping cylinder means 1 (as mentioned above) comprising a
piston 5 inserted freely slidably in acylinder 3.Said piston 5 divides saidcylinder 3 into an upper oil chamber S1 and a lower oil chamber S2. Said suspension device is further provided with a pressure regulator 2 (as mentioned above) comprising apiston 24 inserted freely slidably in acylinder 22. Saidpiston 24 divides saidcylinder 22 into an upper oil chamber S31 and a lower oil chamber S32 each connected with one of the upper and lower oil chamber S1,S2 of the hydraulic damping cylinder means 1, respectively.Said piston 5 of the hydraulic damping cylinder means 1 is a valve seat member and is provided with at least one damping valve as mentioned above, and saidcommunication hole 14 is provided for working oil flow from one of the upper and lower oil chamber to the other thereof, and/or saidpiston 24 ofpressure regulator 2 is a valve seat member and is provided with at least two damping valves as mentioned above, and acommunication hole 26 of a first damping valve is provided for working oil flow from the lower oil chamber S32 to the upper oil chamber S31 and acommunication hole 27 of a second damping valve is provided for working oil flow from the upper oil chamber S31 to the lower oil chamberS32. Said piston 24 of thepressure regulator 2 within the vehicle suspension device serves as a valve seat member which is common for both damping valves so that the mentioned first and second damping valve with the common valve seat member (piston 24) constitute a single bi-directional damping valve.
Claims (11)
- Damping valve for a hydraulic damping means with a valve seat member (5,24) provided with at least one communication hole (14,26,27) for a working oil flow and at least one sheet valve (16,28,29) for opening and closing said communication hole (14,26,27), said sheet valve (16,28,29) has a main valve sheet (16a,28a,29a) and at least one sub-valve sheet (16b,28b,29b) placed with one over the other with the sub-valve sheet (16b,28b,29b) located down-streams with regard to a working oil flow direction, wherein an oil chamber (S) is provided between main valve sheet (16a,28a,29a) and a sub-valve sheet (16b,28b,29b), and wherein at least one orifice (21,26,27) is provided in said main valve sheet (16a,28a,29a) connecting the oil chamber (S) with the communication hole (14,26,27).
- Damping valve according to claim 1, wherein the main valve sheet (16a,28a,29a) and the sub-valve sheet (16b,28b,29b) are ring-shaped, with their inside circumferential portions fixed to the valve seat member (5,24) and with their outside circumferential portions deflectable.
- Damping valve according to claim 2, wherein the main valve sheet (16a,28a,29a) and the sub-valve sheet (16b,28b,29b) having different diameters.
- Damping valve according to claim 2 or 3, wherein the outside circumferential portion the main valve sheet (16a,28a,29a) is in tightened contact with the valve seat member (5,24) and the outside circumferential portion of the sub-valve sheet (16b,28b,29b) is in tightened contact with the main valve sheet (16a,28a,29a).
- Damping valve according to at least one of the claims 2 to 4, wherein an initial deflection is given to the outside circumferential portion of the main valve sheet (16a,28a,29a), said main valve sheet (16a,28a,29a) with the initial deflection is bent back in the working oil flow direction, and the oil chamber (S) is formed with a concave surface of the main valve sheet (16a,28a,29a) and a facing surface of the sub-valve (16b,28b,29b).
- Damping valve according to at least one of the claims 2 to 5, wherein a shim (19) is interposed between the inside circumferential portions of the main valve sheet (16a,28a,29a) and the sub-valve sheet (16b,28b,29b), and both of the valve sheets are secured to the valve seat member (5,24).
- Damping valve according to at least one of the claims 1 to 6, wherein a plurality of the communication holes (14,26,27) are bored in positions approximately on a single circle in the valve seat member (5,24).
- Damping valve according to at least one of the claims 1 to 7, wherein a rigidity of the sub-valve sheet (16b) is set lower than that of the main valve sheet (16a).
- Hydraulic damping cylinder means comprising a piston (5) inserted freely slidably in a cylinder (3), said piston (5) divides said cylinder (3) into an upper oil chamber (S1) and a lower oil chamber (S2), wherein said piston (5) is a valve seat member and is provided with at least one damping valve according to at least one of the claims 1 to 8, and said communication hole (14) is provided for working oil flow from one of the upper and lower oil chamber to the other thereof.
- Pressure regulator comprising a piston (24) inserted freely slidably in a cylinder (22), said piston (24) divides said cylinder (22) into an upper oil chamber (S31) and a lower oil chamber (S32) each connected with a hydraulic damping cylinder means, respectively, wherein said piston (24) is a valve seat member and is provided with at least two damping valves according to at least one of the claims 1 to 8, and a communication hole (26) of a first damping valve is provided for working oil flow from the lower oil chamber (S32) to the upper oil chamber (S31) and a communication hole (27) of a second damping valve is provided for working oil flow from the upper oil chamber (S31) to the lower oil chamber (S32).
- Suspension device for a four wheeled vehicle with at least two hydraulic damping cylinder means (1) comprising a piston (5) inserted freely slidably in a cylinder (3), said piston (5) divides said cylinder (3) into an upper oil chamber (S1) and a lower oil chamber (S2),
and with a pressure regulator (2) comprising a piston (24) inserted freely slidably in a cylinder (22), said piston (24) divides said cylinder (22) into an upper oil chamber (S31) and a lower oil chamber (S32) each connected with one of the upper and lower oil chamber (S1,S2) of the hydraulic damping cylinder means, respectively, wherein said piston (5) of the hydraulic damping cylinder means (1) is a valve seat member and is provided with at least one damping valve according to at least one of the claims 1 to 8, and said communication hole (14) is provided for working oil flow from one of the upper and lower oil chamber to the other thereof,
and/or
wherein said piston (24) of the pressure regulator (2) is a valve seat member and is provided with at least two damping valves according to at least one of the claims 1 to 8, and a communication hole (26) of a first damping valve is provided for working oil flow from the lower oil chamber (S32) to the upper oil chamber (S31) and a communication hole (27) of a second damping valve is provided for working oil flow from the upper oil chamber (S31) to the lower oil chamber (S32).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000017788 | 2000-01-21 | ||
JP2000017788A JP2001208123A (en) | 2000-01-21 | 2000-01-21 | Hydraulic buffer |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1118793A2 true EP1118793A2 (en) | 2001-07-25 |
EP1118793A3 EP1118793A3 (en) | 2002-01-30 |
Family
ID=18544737
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP01101094A Withdrawn EP1118793A3 (en) | 2000-01-21 | 2001-01-18 | Hydraulic damping valve |
Country Status (3)
Country | Link |
---|---|
US (1) | US20010009214A1 (en) |
EP (1) | EP1118793A3 (en) |
JP (1) | JP2001208123A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2834028A1 (en) * | 2001-12-21 | 2003-06-27 | Volkswagen Ag | Vibration damper valve comprises base body and flexible valve discs which, at rest, seal flow path and open at adjusted pressure level of fluid inflow |
CN104169608A (en) * | 2012-03-28 | 2014-11-26 | 萱场工业株式会社 | Damping valve |
CN111065838A (en) * | 2017-10-04 | 2020-04-24 | 株式会社昭和 | Pressure damper device and damping force generating mechanism |
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KR20030018558A (en) * | 2001-08-30 | 2003-03-06 | 현대자동차주식회사 | A shock absorber in vehicle |
US7070029B2 (en) * | 2003-09-15 | 2006-07-04 | Tenneco Automotive Operating Company Inc. | Monotube piston valving system with selective bleed |
DE10347219A1 (en) * | 2003-10-10 | 2005-05-12 | Bayerische Motoren Werke Ag | Method for vibration damping |
KR101053500B1 (en) * | 2004-08-23 | 2011-08-03 | 주식회사 만도 | Shock Absorber Piston Valves |
JP2006132555A (en) * | 2004-11-02 | 2006-05-25 | Kayaba Ind Co Ltd | Damping force generating structure |
JP4368779B2 (en) * | 2004-11-04 | 2009-11-18 | カヤバ工業株式会社 | Molding method of piston nut |
US7628259B2 (en) * | 2004-11-08 | 2009-12-08 | Thyssenkrupp Bilstein Of America, Inc. | Fluid flow regulation of a vehicle shock absorber/damper |
WO2008010813A1 (en) * | 2006-07-21 | 2008-01-24 | Specialized Bicycle Components, Inc. | Bicycle suspension damping system |
US8083039B2 (en) * | 2007-08-29 | 2011-12-27 | Tenneco Automotive Operating Company, Inc. | Disc spring intake |
US8997953B2 (en) * | 2007-08-30 | 2015-04-07 | Tenneco Automotive Operating Company Inc. | Shock absorber having a full displacement valve assembly |
JP2009209960A (en) * | 2008-02-29 | 2009-09-17 | Hitachi Ltd | Shock absorber |
AU2010213371A1 (en) * | 2009-02-16 | 2011-09-22 | Phillip Di Maria | Active suspension system and hydraulic ram therefor |
JP5486393B2 (en) * | 2010-05-07 | 2014-05-07 | カヤバ工業株式会社 | Pneumatic shock absorber |
JP5491952B2 (en) * | 2010-05-07 | 2014-05-14 | カヤバ工業株式会社 | Pneumatic shock absorber |
US8739948B2 (en) * | 2011-02-04 | 2014-06-03 | Tenneco Automotive Operating Company Inc. | Support washer for shock absorber valve with blow-off tunability |
US9080629B2 (en) | 2012-09-07 | 2015-07-14 | Tenneco Automotive Operating Company Inc. | Multi-tuneable degressive valve |
US10239376B2 (en) | 2016-09-22 | 2019-03-26 | Beijingwest Industries Co., Ltd. | Hydraulic damper with an x-flow piston assembly |
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FR2834028A1 (en) * | 2001-12-21 | 2003-06-27 | Volkswagen Ag | Vibration damper valve comprises base body and flexible valve discs which, at rest, seal flow path and open at adjusted pressure level of fluid inflow |
CN104169608A (en) * | 2012-03-28 | 2014-11-26 | 萱场工业株式会社 | Damping valve |
CN111065838A (en) * | 2017-10-04 | 2020-04-24 | 株式会社昭和 | Pressure damper device and damping force generating mechanism |
US11674558B2 (en) | 2017-10-04 | 2023-06-13 | Hitachi Astemo, Ltd. | Hydraulic shock absorber and damping force generation mechanism |
Also Published As
Publication number | Publication date |
---|---|
JP2001208123A (en) | 2001-08-03 |
EP1118793A3 (en) | 2002-01-30 |
US20010009214A1 (en) | 2001-07-26 |
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